// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "content/browser/browsing_instance.h"

#include "base/command_line.h"
#include "base/logging.h"
#include "content/browser/site_instance_impl.h"
#include "content/common/site_isolation_policy.h"
#include "content/public/browser/browser_context.h"
#include "content/public/browser/content_browser_client.h"
#include "content/public/common/content_switches.h"
#include "content/public/common/url_constants.h"

namespace content {

BrowsingInstance::BrowsingInstance(BrowserContext* browser_context)
    : browser_context_(browser_context)
    , active_contents_count_(0u)
{
}

bool BrowsingInstance::HasSiteInstance(const GURL& url)
{
    std::string site = SiteInstanceImpl::GetSiteForURL(browser_context_, url)
                           .possibly_invalid_spec();

    return site_instance_map_.find(site) != site_instance_map_.end();
}

scoped_refptr<SiteInstanceImpl> BrowsingInstance::GetSiteInstanceForURL(
    const GURL& url)
{
    std::string site = SiteInstanceImpl::GetSiteForURL(browser_context_, url)
                           .possibly_invalid_spec();

    SiteInstanceMap::iterator i = site_instance_map_.find(site);
    if (i != site_instance_map_.end())
        return i->second;

    // No current SiteInstance for this site, so let's create one.
    scoped_refptr<SiteInstanceImpl> instance = new SiteInstanceImpl(this);

    // Set the site of this new SiteInstance, which will register it with us.
    instance->SetSite(url);
    return instance;
}

scoped_refptr<SiteInstanceImpl>
BrowsingInstance::GetDefaultSubframeSiteInstance()
{
    // This should only be used for --top-document-isolation mode.
    CHECK(SiteIsolationPolicy::IsTopDocumentIsolationEnabled());
    if (!default_subframe_site_instance_) {
        SiteInstanceImpl* instance = new SiteInstanceImpl(this);
        instance->set_is_default_subframe_site_instance();

        // TODO(nick): This is a hack for now.
        instance->SetSite(GURL("http://web-subframes.invalid"));

        default_subframe_site_instance_ = instance;
    }

    return make_scoped_refptr(default_subframe_site_instance_);
}

void BrowsingInstance::RegisterSiteInstance(SiteInstanceImpl* site_instance)
{
    DCHECK(site_instance->browsing_instance_.get() == this);
    DCHECK(site_instance->HasSite());

    // Don't register the default subframe SiteInstance, to prevent it from being
    // returned by GetSiteInstanceForURL.
    if (default_subframe_site_instance_ == site_instance)
        return;

    std::string site = site_instance->GetSiteURL().possibly_invalid_spec();

    // Only register if we don't have a SiteInstance for this site already.
    // It's possible to have two SiteInstances point to the same site if two
    // tabs are navigated there at the same time.  (We don't call SetSite or
    // register them until DidNavigate.)  If there is a previously existing
    // SiteInstance for this site, we just won't register the new one.
    SiteInstanceMap::iterator i = site_instance_map_.find(site);
    if (i == site_instance_map_.end()) {
        // Not previously registered, so register it.
        site_instance_map_[site] = site_instance;
    }
}

void BrowsingInstance::UnregisterSiteInstance(SiteInstanceImpl* site_instance)
{
    DCHECK(site_instance->browsing_instance_.get() == this);
    DCHECK(site_instance->HasSite());
    std::string site = site_instance->GetSiteURL().possibly_invalid_spec();

    // Only unregister the SiteInstance if it is the same one that is registered
    // for the site.  (It might have been an unregistered SiteInstance.  See the
    // comments in RegisterSiteInstance.)
    SiteInstanceMap::iterator i = site_instance_map_.find(site);
    if (i != site_instance_map_.end() && i->second == site_instance) {
        // Matches, so erase it.
        site_instance_map_.erase(i);
    }
    if (default_subframe_site_instance_ == site_instance)
        default_subframe_site_instance_ = nullptr;
}

BrowsingInstance::~BrowsingInstance()
{
    // We should only be deleted when all of the SiteInstances that refer to
    // us are gone.
    DCHECK(site_instance_map_.empty());
    DCHECK_EQ(0u, active_contents_count_);
}

} // namespace content
